Zoe Giannioudis was a stressed out, severely underweight 30-year-old drug dealer feeding her own $400-a-day heroin habit when she crossed paths with the wrong man on the wrong day.

The 45kg Collingwood-based dealer had been trying to make sales on the main thoroughfare in Melbourne’s heroin capital — Victoria Street at Richmond. It was raining so customers were few and far between.

She was carrying a knife for protection when Simon Cartwright, a customer she knew well, crossed the street towards her. She stabbed him in the chest while he held a washing basket. His injuries were fatal.

The pair were known to one another. They had previously exchanged terse messages. They had previously made threats. He stabbed her in the arm on one occasion and made a lewd remark about watching her perform sexual acts with his girlfriend and her girlfriend on another occasion.

“After a brief interaction, you produced a knife and stabbed Mr Cartwright once to the chest. His partner heard him cry out in pain and ran to him. She observed you holding a knife. He lifted his shirt to reveal heavy bleeding,” Justice Taylor said.